Punch presses commonly have an actuating ram, an upper platform which holds a punching tool, and a lower platform that supports a die in vertical alignment with the punching tool. Turret-type punch presses utilize a rotatable upper platform that has a series of tool mounting stations arranged around its periphery for receiving different punching or marking tools. Rotation of the platform brings a selected punch into position above a work station and beneath the ram. A lower platform is provided with a corresponding series of dies, and is rotatable with the upper platform to enable the proper die to be aligned with a selected punch.
Certain punch tools themselves can be "multi-tools." That is, a punching tool, instead of containing only a single punch, may contain a magazine bearing a series of vertically movable punches in circumferentially spaced bores. The magazine itself can be rotated, as by a worm gear or the like, about a central vertical axis so as to place the correct punch above a work piece in a work station. Multi-tool mechanisms of this type are used, for example, for punching selected numbers or letters into a work piece, as well as for punching holes through the thickness of a work piece. A lower magazine containing a plurality of corresponding dies also may be provided so that as the magazine containing the punches is rotated about its axis, the lower magazine is rotated as well to bring the appropriate die into vertical alignment with the selected punch.
Carried above a multi-tool magazine is a multi-tool carrying a striker. As the multi-tool is struck downwardly by the ram of a punch press, the striker is forced downwardly into contact with a vertically aligned punch, causing that punch in turn to strike the work piece. The width of the striker at its bottom end is generally less than the distance between adjacent punches in the magazine, so that the striker cannot strike more than one punch at a time.
The multi-tool commonly is prevented by its contact with the punch press ram from rotating as the magazine is rotated about its axis to bring a selected tool into vertical alignment with the striker. In a typical procedure, the punch press ram descends into a rotationally locking engagement with the multi-tool, following which the magazine is rotated to bring a selected punch into alignment with the striker, and then the multi-tool is depressed further by the ram to cause the striker to engage the aligned punch in a punching operation.
The striker housing and tool ram have faces configured so that when they are brought together, the striker housing is rotationally locked to the punch press ram. The punch press ram, for example, may have a flat, generally rectangular shaped bottom surface that is received into a complementary slot or other configuration of the striker housing so that the striker housing is held rotationally stationary by the punch press ram.
A problem arises with certain punch presses in that the precise angular position of the punch press ram cannot be assured each time the striker housing is positioned over a tool ram. Rotational misalignment between the punch press ram and the striker housing may only be on the order of a few degrees, but may yet be sufficient to prevent the striker housing and the punch press ram from rotationally locking together. Rotational misalignment of the ram with the striker housing may prevent the punch press ram, as it descends into contact with the striker housing, from rotationally locking to the striker housing. The striker housing itself hence may undergo some rotation as the magazine is rotated, with the result that the striker is not aligned with the correct punching tool. The work piece accordingly may be ruined, and substantial damage may result to the striker housing.
It would be desirable to correct any misalignment of the striker housing and the punch press ram so as to enable them to rotationally lock together and prevent rotation of the striker housing as the tool magazine is rotated beneath it.